scholarly journals Influence of Carrier Gases on the Quality of Epitaxial Corundum-Structured α-Ga2O3 Films Grown by Mist Chemical Vapor Deposition Method

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3670 ◽  
Author(s):  
Yu Xu ◽  
Chunfu Zhang ◽  
Yaolin Cheng ◽  
Zhe Li ◽  
Ya’nan Cheng ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Lattice Structure ◽  
Chemical Vapor ◽  
Crystal Quality ◽  
Chemical Vapor Deposition Method ◽  
Carrier Gas ◽  
Perfect Lattice ◽  
Atomic Force ◽  
Carrier Gases

This report systematically investigates the influence of different carrier gases (O2, N2, and air) on the growth of gallium oxide (Ga2O3) thin films on c-plane sapphire substrates by using the mist-CVD method. Although XRD and Raman measurements show that the pure corundum-structured α-Ga2O3 with single (0006) plane orientation was successfully obtained for all three different carrier gases, the crystal quality could be greatly affected by the carrier gas. When O2 is used as the carrier gas, the smallest full-width at half maximum (FWHM), the very sharp absorption cutoff edge, the perfect lattice structure, the highest growth rate, and the smooth surface can be obtained for the epitaxial α-Ga2O3 film as demonstrated by XRD, UV-VIS, TEM, AFM (Atomic Force Microscope), and SEM measurements. It is proposed that the oxygen content in carrier gas should be responsible for all of these results. XPS (X-ray photoelectron spectroscopy) analysis also confirms that more oxygen elements can be included in epitaxial film when O2 is used as the carrier gas and thus help improve the crystal quality. The proper carrier gas is essential for the high quality α-Ga2O3 growth.

scholarly journals Fabrication and Physical Properties of Single-Crystalline Βeta-FeSi2 Nanowires

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Chih-Yung Yang ◽  
Shu-Meng Yang ◽  
Yu-Yang Chen ◽  
Kuo-Chang Lu
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Field Emitters ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Carrier Gases

Abstract In this study, self-catalyzed β-FeSi2 nanowires, having been wanted but seldom achieved in a furnace, were synthesized via chemical vapor deposition method where the fabrication of β-FeSi2 nanowires occurred on Si (100) substrates through the decomposition of the single-source precursor of anhydrous FeCl3 powders at 750–950 °C. We carefully varied temperatures, duration time, and the flow rates of carrier gases to control and investigate the growth of the nanowires. The morphology of the β-FeSi2 nanowires was observed with scanning electron microscopy (SEM), while the structure of them was analyzed with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The growth mechanism has been proposed and the physical properties of the iron disilicide nanowires were measured as well. In terms of the magnetization of β-FeSi2, nanowires were found to be different from bulk and thin film; additionally, longer β-FeSi2 nanowires possessed better magnetic properties, showing the room-temperature ferromagnetic behavior. Field emission measurements demonstrate that β-FeSi2 nanowires can be applied in field emitters.

Experimental Study of the Effect of Precursor Composition On the Microstructure of Gallium Nitride Thin Films Grown by the MOCVD Process

2021 ◽  
Author(s):  
Omar D. Jumaah ◽  
Yogesh Jaluria
Keyword(s):  
Thin Films ◽  
Gallium Nitride ◽  
Chemical Vapor Deposition ◽  
Deposition Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Transport Processes ◽  
Carrier Gas ◽  
Precursor Composition

Abstract Chemical vapor deposition (CVD) is a widely used manufacturing process for obtaining thin films of materials like silicon, silicon carbide, graphene and gallium nitride that are employed in the fabrication of electronic and optical devices. Gallium nitride (GaN) thin films are attractive materials for manufacturing optoelectronic device applications due to their wide band gap and superb optoelectronic performance. The reliability and durability of the devices depend on the quality of the thin films. The metal-organic chemical vapor deposition (MOCVD) process is a common technique used to fabricate high-quality GaN thin films. The deposition rate and uniformity of thin films are determined by the thermal transport processes and chemical reactions occurring in the reactor, and are manipulated by controlling the operating conditions and the reactor geometrical configuration. In this study, the epitaxial growth of GaN thin films on sapphire (AL2O3) substrates is carried out in two commercial MOCVD systems. This paper focuses on the composition of the precursor and the carrier gases, since earlier studies have shown the importance of precursor composition. The results show that the flow rate of trimethylgallium (TMG), which is the main ingredient in the process, has a significant effect on the deposition rate and uniformity of the films. Also the carrier gas plays an important role in deposition rate and uniformity. Thus, the use of an appropriate mixture of hydrogen and nitrogen as the carrier gas can improve the deposition rate and quality of GaN thin films.

Synthesis of Crystalline Carbon Nitride by Microwave Plasma Chemical Vapor Deposition

2005 ◽  
Vol 480-481 ◽  
pp. 71-76 ◽  
Author(s):  
Jin Chun Jiang ◽  
Wen Juan Cheng ◽  
Yang Zhang ◽  
He Sun Zhu ◽  
De Zhong Shen
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Plasma Chemical ◽  
X Ray ◽  
Plasma Chemical Vapor Deposition

Carbon nitride films were grown on Si substrates by a microwave plasma chemical vapor deposition method, using mixture of N2, CH4 and H2 as precursor. Scanning electron microscopy shows that the films consisted of a large number of hexagonal crystallites. The dimension of the largest crystallite is about 3 µm. The X-ray photoelectron spectroscopy suggests that nitrogen and carbon in the films are bonded through hybridized sp2 and sp3 configurations. The X-ray diffraction pattern indicates that the major part of the films is composed of α-, β-, pseudocubic C3N4 and graphitic C3N4. The Raman peaks match well with the calculated Raman frequencies of α- and β-C3N4, revealing the formation of the α- and β-C3N4 phase.

scholarly journals Area Selective Deposition of Metal Films Using Temperature Sensitive Masking Materials and Plasma Electrons as Reducing Agents

2021 ◽  
Author(s):  
Hama Nadhom ◽  
Yusheng Yuan ◽  
Polla Rouf ◽  
Niclas Solin ◽  
Henrik Pedersen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Chemical Vapor ◽  
Metal Films ◽  
Reducing Agents ◽  
Film Deposition ◽  
Chemical Vapor Deposition Method ◽  
Temperature Sensitive ◽  
Film Material ◽  
Selective Deposition

<p>The potential of area selective deposition (ASD) with a newly developed chemical vapor deposition method, which utilize plasma electrons as reducing agents for deposition of metal films, is demonstrated using temperature sensitive polymer-based masking materials. The masking materials tested were polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA), polystyrene (PS), parafilm, Kapton tape, Scotch tape, and office paper. The masking materials where all shown to prevent film growth on the masked area of the substrate without being affected by the film deposition process. X-ray photoelectron spectroscopy analysis confirms that the film deposited consist mainly of metallic iron, whereas no film material is found on the masked areas after mask removal. SEM analysis of films deposited with non‑adhesive masking materials show that film growth extended for a small distance underneath the masking material, indicating that the CVD process with plasma electrons as a reducing agent is not a line-of-sight deposition technique. The reported methodology introduces an inexpensive and straightforward approach for ASD that opens for exciting new possibilities for robust and less complex area selective metal‑on‑metal deposition. </p>

scholarly journals Investigation on the Selenization Treatment of Kesterite Cu2Mg0.2Zn0.8Sn(S,Se)4 Films for Solar Cell

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 946 ◽  
Author(s):  
Dongyue Jiang ◽  
Yu Zhang ◽  
Yingrui Sui ◽  
Wenjie He ◽  
Zhanwu Wang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Crystal Quality ◽  
Crystalline Quality ◽  
Soda Lime Glass ◽  
Soda Lime Glass Substrate ◽  
X Ray ◽  
Morphological Studies ◽  
Selenization Temperature

High-selenium Cu2Mg0.2Zn0.8Sn(S,Se)4 (CMZTSSe) films were prepared on a soda lime glass substrate using the sol–gel spin coating method, followed by selenization treatment. In this work, we investigated the effects of selenization temperature and selenization time on the crystal quality, and electrical and optical properties of CMZTSSe films. The study on the micro-structure by XRD, Raman, X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS) analysis showed that all CMZTSSe samples had kesterite crystalline structure. In addition, the crystalline quality of CMZTSSe is improved and larger Se takes the site of S in CMZTSSe with the increase of selenization temperature and selenization time. When increasing the selenization temperature from 500 to 530 °C and increasing the annealing time from 10 to 15 min, the morphological studies showed that the microstructures of the films were dense and void-free. When further increasing the temperature and time, the crystalline quality of the films began to deteriorate. In addition, the bandgaps of CMZTSSe are tuned from 1.06 to 0.93 eV through adjusting the selenization conditions. When CMZTSSe samples are annealed at 530 °C for 15 min under Se atmosphere, the crystal quality and optical–electrical characteristics of CMZTSSe will be optimal, and the grain size and carrier concentration reach maximums of 1.5–2.5 μm and 6.47 × 1018 cm−3.

Surface Modification of Polyetheretherketone by Helium/nitrogen and Nitrous Oxide Plasma Enhanced Chemical Vapour Deposition

2014 ◽  
Vol 33 (2) ◽  
pp. 147-153
Author(s):  
Stanisława Kluska ◽  
Elżbieta Pamuła ◽  
Stanisława Jonas ◽  
Zbigniew Grzesik
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Chemical Vapour ◽  
Chemical Vapor ◽  
Morphological Characterization ◽  
Polar Component ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe surface of the polyetheretherketone (PEEK) samples was modified by the plasma enhanced chemical vapor deposition (PECVD) in the mixture of He and N2 as well as in the N2O atmosphere. Morphological characterization of the PEEK as well as its surface roughness, chemical structure, and surface free energy were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and sessile drop technique, respectively. The highest increase in the polar component of the total surface energy was observed for PEEK modified by He+N2 plasma, which correlated with significant increase in the concentration of oxygen and nitrogen-containing chemical functionalities as revealed by XPS. For PEEK submitted to N2O plasma treatment significant changes in surface topography and increase in roughness were observed, but changes in surface chemistry and surface free energy were mild.

Study of Depth-Dependent Tetragonal Distortion of GaN Epilayer with Tri-Layer AlGaN Interlayer Growth on Si(111)

2011 ◽  
Vol 413 ◽  
pp. 11-17 ◽  
Author(s):  
Bin Feng Ding ◽  
Yong Quan Chai
Keyword(s):  
Chemical Vapor ◽  
Crystal Quality ◽  
Tetragonal Distortion ◽  
Organic Chemical ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

A GaN epilayer with tri-layer AlGaN interlayer grown on Si (111) by metal-organic chemical vapor deposition (MOCVD) method was discussed by synchrotron radiation x-ray diffraction (SRXRD) and Rutherford backscattering (RBS)/C. The crystal quality of the epilayer is very good with a χmin=2.1%. According to the results of the θ-2θ scan of GaN(0002) and GaN(1122), the epilayer elastic strains in perpendicular and parallel directions were calculated respectively to be-0.019% and 0.063%. By the angular scan using RBS/C around a symmetric [0001] axis and an asymmetric [1213] axis in the (1010) plane of the GaN layer, the tetragonal distortion (eT ) were determined to be 0.09%. This result coincides with that from SRXRD perfectly. The strain decreases gradually towards the near-surface layer, which will avoid the film cracks efficiently and improve the crystal quality of the GaN epilayer remarkably.

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